PESHAWAR: A key border crossing between Pakistan and Afghanistan remained closed for a third day, with thousands of goods vehicles stuck and businesses facing losses as officials from both sides try to broker a solution.

Taliban authorities on Sunday closed Torkham, the main point of transit for travellers and goods between Pakistan and landlocked Afghanistan.

"The closure of the border crossing between Pakistan and Afghanistan has been causing losses to traders of the two countries. There are long queues of heavy trucks stranded on both sides of the border," said Zia-ul-Haq Sarhadi, director of the Pakistan-Afghanistan Joint Chamber of Commerce and Industry.

He said up to 6,000 trucks loaded with goods had been stuck on both sides since Sunday.

The reason for the closure was not entirely clear, though officials on both sides have said they were in discussions to resolve the issue. A provincial Taliban official told Reuters on Monday Pakistan had not lived up to its commitments to allow transit, travellers and sick people seeking treatment to cross.

Pakistan's government has not commented publicly on the matter. A Pakistani official source said they had not been told the reason ahead of the closure.

Sarhadi said Afghanistan relied on goods from Pakistan for much of its needs and many trucks were also destined for Central Asia using Afghanistan as a transit point.

"The traders and particularly those supplying fresh food items such as fruits, vegetables, are facing losses as trucks are stranded on the way for the past three days," he said.

He added some trucks had been diverted to another, smaller border crossing, but traders were worried about the security of truck drivers travelling to that region.

Residents had reported heavy gunfire on Monday morning near the Torkham border crossing, but the Taliban official had denied any clashes and said the situation was under control.

Disputes linked to the 2,600 km (1,615 mile) border have been a bone of contention between the neighbours for decades.